Which of the following is NOT a feature of Mendeleev's periodic classification?
Correct position of isotopes.
Mendeleev arranged the known elements in groups and periods largely by atomic mass and by their similar physical and chemical properties.
He famously left gaps and predicted properties of undiscovered elements such as eka-aluminium (gallium) and eka-silicon (germanium).
However, his table gave no consistent slot for isotopes of the same element, since they share properties but differ in mass.
Hence Correct position of isotopes. is NOT a feature of his classification.
The element with the symbol K is:
Which of the following pairs is correctly matched?
Which of the following element symbols does NOT match its element?
Which of the following statements is/are true?
A. Out of 114 elements, 32 are non-metals and others are metals.
B. Every ore is a mineral but every mineral is not an ore.
What is the characteristic of Rare Earth Elements?
Which elements were named by Mendeleev by adding the prefix 'Eka' before the name of the preceding element in the same group?
In Mendeleev's periodic table, the horizontal rows are called:
Group ____ contain non-reactive gases.
The chemical properties of the element having which of the following atomic numbers are similar to magnesium?
The modern periodic table has:
The correct order of decreasing electron gain enthalpy with negative sign for chalcogens is - Identify
Modern periodic table has:
‘Triclosan’, considered harmful when exposed to high levels for a long time, is most likely present in which of the following?
____________ is also known as Quick lime.